Rpms?

[valencehsift]

Ok, first real run out on my first boat. The rpm guage seems to work. I am getting just over 6000 rpm if I want on my 1989 Force 150 which is full throtle but is also red lining. Is this normal and is it ok to run it like that for a while?

Also need advice on changing the speedometer, would love to know my top end as it seems impressive.

 

[kenmyfam]

Re: Rpms?

Force experts out here will tell you all about the max RPM for your motor. 2 strokes thrive on RPM up to the max for the motor in question.
As regards the speed, I have a speedometer on mine but usually go by my hand held GPS. Worth having on board for other obvious reasons as well and is more accurate than most speedometers.

 

[roscoe]

Re: Rpms?

Boat speedometers are pretty much worthless and inaccurate.

For the time, money and effort involved in getting one, you might as well just pick up a cheap handheld gps and be done with it.

As far as rpm go, you are pushing it a bit with that motor.
It is time to change props and get the rpms down where they belong, 5500.

For help in choosing the correct prop, post a question in the prop forum.

 

[skibug]

Re: Rpms?

Not sure about the 150, but my 120 force has a max rpm of 5200. Check the ID plate on the motor. It gives the max rpm.

 

[steelespike]

Re: Rpms?

My after market repair manual says 5,000 to 5,500.You should confirm your tach is accurate. Try to beg or borrow a tach. possibly buy a tiny tach about $40 easy to install and may be able to be ordered to work on different motors.